Technical Field
The present invention relates to a substituent-eliminable diketopyrrolopyrrole derivative, an organic semiconductor material precursor solution, an organic semiconductor material, and an organic semiconductor material film.
Description of the Related Art
Recently, there has been an increase in research and development for sensors using organic semiconductor materials, organic light-emitting diodes, organic field-effect transistors, and organic semiconductors for solar cells.
Materials soluble in organic solvents are known as organic semiconductor materials. Such materials are easily processible into thin films by simple wet processes, such as printing process and spin coat process, even on plastic substrates that will have low heat resistance. The utility of plastic substrates in combination with such materials soluble in organic solvents leads to reduction in weight and cost for resulting electronic devices such as displays. Various other applications are expected owing to such a flexibility of plastic substrates.
Japanese Patent Application Publication No. 2011-501743 discloses a derivative of low-molecular-weight diketopyrrolopyrrole as a p-type semiconductor material for use in solar cells. The derivative has a thiophene ring to which a long straight-chain or branched-chain alkyl group is directly introduced to the third or fourth position thereof.
U.S. Patent Application Publication No. 2010/0326525 also discloses a derivative of low-molecular-weight diketopyrrolopyrrole. The derivative has a thiophene ring to which an alkyl group is directly introduced to the fifth position thereof. Both of the references have attempted to introduce long-chain alkyl group to diketopyrrolopyrrole derivative to improve its solubility in organic solvents and compatibility with n-type semiconductor materials for use in solar cells, which may improve incident photoelectric conversion efficiency of solar cells.